Entry Interface Envelope Evaluation for Reusable Spaceplanes Using Sequential Convex Programming

초록

The reentry flight of a spacecraft is a critical phase that requires safeguarding the vehicle against extreme heat and pressure, while ensuring a precise return to a predetermined ground location. The permissible flight envelope for an undamaged return is notably restrictive, thereby complicating the trajectory optimization challenge. This study introduces a reentry problem formulated through sequential convex optimization, aimed at identifying a viable reentry envelope that assures safe return upon mission completion. A grid search is employed to identify a reentry envelope within which the optimization problem can consistently yield feasible solutions. The Sequential Convex Programming (SCP) algorithm, known for its efficacy in managing complex nonlinear dynamics and nonconvex constraints, is employed to solve the trajectory optimization problem. Furthermore, to overcome the numerical sensitivity of SCP, a trust-region update technique is incorporated, enabling the algorithm to reliably find solutions across various initial conditions. The proposed algorithm is validated via numerical simulations, and the reentry envelope is assessed by varying the initial latitude and longitude conditions. This approach guarantees that the algorithm produces feasible trajectories that satisfy all specified dynamics and constraints.

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